1.16.2010

How Seiko Kinetic Watches Compare With Citizen Eco-Drive For Divers

Both these companies make great products, but they do so utilizing completely different technologies. So which is best, and further more which is the better choice when considering purchasing a dive watch.

On the one hand, Seiko kinetic dive watches utilize motion, or kinetic energy drived from movement, while the Citizen Eco-Drive Titanium watch incorporates solar panels to capture energy from various light sources. On the surface, the most observable difference is that the latter relies on fewer moving parts.
  

-------------Citizen Eco-Drive--------------
  

Of course, fewer parts is always better in terms of long-term reliability, however in the case of a watch it’s likely more of a moot point since analog watches are already composed of more parts than one could count, so what real difference will a few more make.

First, some history on how both these power systems function will be useful before drilling down to deciding which is best. Obviously, this discussion has nothing to do with watches requiring daily winding either. Leave that to the over-priced Rolex still lost in the last century.

Seiko pioneered the self-winding watch back in 1980. They came up with a way to translate the motion of the wearers arm movements into the mechanical energy necessary to wind the watches mainspring. The fancy word kinetic simply means motion-generated mechanical energy.

They do this by having arm motion swing an odd-shaped rotor, weighted heavily on one side, around a winding mechanism that, with the use of special reversed gearing, will only move in one direction. The result is a winding of the mainspring over time.

This in itself will keep the watch wound as long as it’s worn and thus receiving kinetic energy input. But if left off the arm for a day or two, it will stop. This is especially important since the focus here is on dive watches, which might not be worn as a regular everyday watch.

To resolve this problem, Seiko added a battery as a place to store the excess kinetic energy. Assuming the battery is fully charged, the watch can now be left lying still for months or even years and still not require winding.

Instead of kinetic energy, Citizen developed a way to utilize light as a power source. And it doesn’t even need to be sunlight – any light source will do fine.

To accomplish this, Citizen places tiny solar cells on the faces of their Eco-Drive watches. These cells are what transform light into electrical energy. This energy is then collected and stored in energy cells, sort of like a battery, that will then supply power for extended periods, even without light.

Again, since the underlying subject is really about dive watches, this is especially useful for someone who only uses the watch for diving, as opposed to wearing it everyday. By storing up energy for later use, these watches can be left idle for extended periods, and still show the correct time upon their next use.
In fact, a lot of the newest models, both solar and kinetic, have something called hibernation mode, where after sensing no movement for an extended period, the hands and dial functions stop moving to save energy. However, the quartz movement will keep on calculating the correct time, so once the watch is moved again, the sensors activate and reset with current data.

Battery technology has come quite far along too, so were now close to the point where this storage cell or battery, could last beyond the lifetime of the wearer. That means the battery would never need replacing, making these watches super friendly to the environment.

So which one is best? Well, if the watch is worn with any amount of regularity, it appears to be a toss up, and either energy source will work fine. You can also see that either type watch can be left idle for long periods of time ranging from months to years, and continue to keep correct time.

I suppose if one left the Citizen Eco-Drive watch in a drawer long enough, it would eventually stop from lack of light, but then again, so would a Seiko kinetic watch from lack of wrist movement.

At the end of the day, it’s somewhat unlikely one will purchase any watch just to leave it lying around for years, so the answer has to be that both energy generation techniques will work well, and it becomes a matter of personal preference.

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